The invention relates to an array substrate of a liquid crystal display device and a method of manufacturing the same.
With the development of technology, liquid crystal display (LCD) devices have been replacing the conventional CRT display devices and become the main type of the next generation display devices. Among various LCD devices, thin film transistor liquid crystal display (TFT-LCD) devises prevail in the market of flat panel display devices due to low power consumption, relatively low manufacturing cost, and low radiation.
A TFT LCD is generally formed by assembling an array substrate and a color filter substrate. The array substrate of the TFT LCD comprises a plurality of gate lines and a plurality of data lines which are perpendicular to the gate lines, and the gate lines and the data lines intersect with each other and define a plurality of pixel regions. Each pixel may comprise a TFT as a switch device, a pixel electrode, and a common electrode. The TFT comprises a gate electrode, a gate insulating layer, an active layer, a source electrode and a drain electrode. The source and drain electrodes can be covered by a passivation layer, a via hole in which is formed above the drain electrode and leads to the drain electrode. The pixel electrode, which is formed on the passivation layer, is connected with the drain electrode of the TFT through the via hole in the passivation layer. A storage capacitor can be formed between a part of the pixel electrode and the gate line.
At present, the display modes of the TFT LCD comprise a Twisted Nematic (TN) mode, an In-Plane-Switching (IPS) mode, a Fringe Field Switching (FFS) mode, and the like. In the FFS mode, the combination of a transparent planar electrode (common electrode) and a finger electrode can form a more appropriate electric field and optimize the arrangement of the liquid crystal molecules; meanwhile, the opaque metal electrode is replaced with a transparent electrode and the transmittivity of pixel can be remarkably improved.
However, in application of the FFS technology, since the pixel electrode on the array substrate is in an arrangement of electrodes of a shape of “” (finger electrodes), the electric field at the boundary between the “/” portion and the “\” portion of the electrode is irregular due to the interaction therebetween, which makes the liquid crystal molecules arranged irregularly and forms a display blind area, which degrades the transmittivity and the display quality of the array substrate. Furthermore, since the power consumption of a backlight source is gradually decreased for the purpose of environmental protection, the transmittivity of pixel has to be improved in order to obtain similar display quality as those before the power consumption of the backlight is decreased.